Title: Decoupling the roles of carbon and metal oxides on the electrocatalytic reduction of oxygen on La_1-xSr_xCoO_3-δ perovskite composite electrodes

Abstract

Perovskite oxides are active room-temperature bifunctional oxygen electrocatalysts in alkaline media, capable of performing the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) with lower combined overpotentials relative to their precious metal counterparts. However, their semiconducting nature necessitates the use of activated carbons as conductive supports to generate applicably relevant current densities. In efforts to advance the performance and theory of oxide electrocatalysts, the chemical and physical properties of the oxide material often take precedence over contributions from the conductive additive. In this work, we find that carbon plays an important synergistic role in improving the performance of La_1-xSr_xCoO_3-δ (0 ≤ x ≤ 1) electrocatalysts through the activation of O₂ and spillover of radical oxygen intermediates, HO₂- and O₂-, which is further reduced through chemical decomposition of HO₂- on the perovskite surface. Here, through a combination of thin-film rotating disk electrochemical characterization of the hydrogen peroxide intermediate reactions (hydrogen peroxide reduction reaction (HPRR), hydrogen peroxide oxidation reaction (HPOR)) and oxygen reduction reaction (ORR), surface chemical analysis, HR-TEM, and microkinetic modeling on La_1-xSr_xCoO_3-δ (0 ≤ x ≤ 1)/carbon (with nitrogen and non-nitrogen doped carbons) composite electrocatalysts, we deconvolute the mechanistic aspects and contributions to reactivity of the oxide and carbonmore » support.« less

Authors:

Mefford, J. Tyler  ^[1];

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• Search DOE PAGES for ORCID "0000-0003-4965-4147"

Kurilovich, Aleksandr A.  ^[2];

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• Search DOE PAGES for ORCID "0000-0002-4923-0574"

Saunders, Jennette ^[3]; Hardin, William G.  ^[4];

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• Search DOE PAGES for ORCID "0000-0003-0557-7434"

Abakumov, Artem M.  ^[5];

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• Search DOE PAGES for ORCID "0000-0002-7135-4629"

Forslund, Robin P. ^[1]; Bonnefont, Antoine  ^[6];

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• Search DOE PAGES for ORCID "0000-0002-5566-3712"

Dai, Sheng  ^[7];

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• Search DOE PAGES for ORCID "0000-0002-8046-3931"

Johnston, Keith P.  ^[8];

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• Search DOE PAGES for ORCID "0000-0002-0915-1337"

Stevenson, Keith J.  ^[2]

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• Search DOE PAGES for ORCID "0000-0002-1082-2871"

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+ Show Author Affiliations

1. Univ. of Texas, Austin, TX (United States). Dept. of Chemistry; Univ. of Texas, Austin, TX (United States). Center for Nano and Molecular Science and Technology
2. Skolkovo Inst. of Science and Technology, Moscow (Russia). Center for Electrochemical Energy Storage CREI
3. Univ. of Texas, Austin, TX (United States). Dept. of Chemistry
4. Univ. of Texas, Austin, TX (United States). Dept. of Chemistry, and Center for Nano and Molecular Science and Technology, Texas Materials Inst.; Exponent Failure Analysis Associates, Natick, MA (United States)
5. Skolkovo Inst. of Science and Technology, Moscow (Russia). Center for Electrochemical Energy Storage CREI; Univ. of Antwerp, Antwerp (Belgium)
6. Univ. of Strasbourg, Strasbourg (France). Inst. de Chimie de Strasbourg
7. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical Sciences Division
8. Univ. of Texas, Austin, TX (United States). Center for Nano and Molecular Science and Technology, Texas Materials Inst., and Dept. of Chemical Engineering

Publication Date:

Fri Jan 18 00:00:00 EST 2019

Research Org.:

Energy Frontier Research Centers (EFRC) (United States). Fluid Interface Reactions, Structures and Transport Center (FIRST); Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1506782

Alternate Identifier(s):

OSTI ID: 1492463

Grant/Contract Number:  

AC05-00OR22725; F-1529; F-1319

Resource Type:

Accepted Manuscript

Journal Name:

Physical Chemistry Chemical Physics. PCCP

Additional Journal Information:

Journal Volume: 21; Journal Issue: 6; Journal ID: ISSN 1463-9076

Publisher:

Royal Society of Chemistry

Country of Publication:

United States

Language:

English

Subject:

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 36 MATERIALS SCIENCE